Channelized receiver system

ABSTRACT

A channelizing receiver is provided with a plurality of channel receivers for monitoring respective segments of a frequency band being monitored by the channelizing receiver. Each channel receiver includes a channel processor for detecting an electromagnetic signal, measuring the peak amplitude of the electromagnetic signal and comparing this peak amplitude with the peak amplitudes for the electromagnetic signal detected by adjacent channel receivers. Data responsive to a detected signal is transmitted from a channel receiver only if the channel receiver&#39;s measured peak amplitude is higher than that for the adjacent channel receivers. The data include an estimate of the frequency and bandwidth of the detected signal made by the channel receiver transmitting the data based upon an assessment of the relative peak amplitudes.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a receiver system for receivingand detecting electromagnetic signals and, in particular, to achannelizing receiver system for receiving and detecting electromagneticsignals and for providing information regarding the characteristics ofthese signals. The present invention also relates to a method fordetecting and characterizing electromagnetic signals using a channelizedreceiver system.

[0002] Systems for scanning and detecting a wide range ofelectromagnetic signals and, in particular radio frequency (RF) signals,and for analyzing the detected signals are widely used for electronicwarfare (EW) and for other military and non-military applications.Systems performing such functions may employ a searching system and ananalyzing system. A channelizing receiver often is used for thesearching system.

[0003] A channelizing receiver typically includes a number of uniformlyspaced, narrow bandwidth receivers which together contiguously cover theentire electromagnetic spectrum of interest. Each narrow bandwidthreceiver (channel receiver) typically includes a log detector, forconverting RF emissions into a log video signal, and a thresholddetector for evaluating the signal generated by the log detector. Theparticular channel receiver of the channelizing receiver providing anoutput signal provides a rough estimate of a detected signal's time ofarrival, pulse width and frequency. If several channel receivers provideoutput signals, the output signal having the greatest magnitude may beused to provide this rough estimate.

[0004] Information from the channelizing receiver often is transmittedto an analyzing receiver. The analyzing receiver performs a moreextensive analysis of the particular signal to precisely measure thesignal's frequency, bandwidth and pulse width and also to determine thesignal's phase and modulation. The information from the channelizingreceiver, however, enables the analyzing receiver to perform thisfunction more efficiently and effectively. By screening noise and othersignals of no interest, the channelizing receiver enables the analyzingreceiver to focus only on the signals of importance.

[0005] Current channelizing receivers suffer, however, from a number ofdeficiencies. First, each channel receiver must be capable of detectingthe majority of electromagnetic emissions within its designatedbandwidth. As a result, the channel receiver cannot be optimized forboth short duration electromagnetic signals and long durationelectromagnetic signals.

[0006] Second, since each channel receiver monitors a contiguous segmentof a broad electromagnetic spectrum, an electromagnetic signal cantrigger output signals from several channel receivers. As a result, theanalyzing system must direct resources, at least temporarily, to resolvewhere in the frequency spectrum the signal is located, and the analyzingsystem often is delayed in directing resources to the signal or signalsof real interest.

[0007] Third, as a result of noise and modulation of a signal's risingand falling edges, an individual channel receiver can falsely reportmultiple detections from a single incoming signal. These falsedetections also waste the resources of the analyzing system.

[0008] As a final matter, the configuration of current channelizingreceivers imposes inherent limitations on signal-to-noise sensitivityand on the quality of information provided to the analyzing system.These inherent limitations reduce the overall quality and reliability ofthese systems.

SUMMARY OF THE INVENTION

[0009] In one aspect, the present invention provides a channelizingreceiver. The channelizing receiver includes a plurality of channelreceivers. Each of the channel receivers includes a plurality offilters, and each of the filters receives an input signal representingelectromagnetic signals falling within a frequency range being monitoredby the channel receiver. Each of the filters also transmits an outputsignal representing electromagnetic signals falling within a segment ofthis frequency range.

[0010] The channelizing receiver further includes a plurality ofthreshold detectors. Each of the threshold detectors receives one of theoutput signals and produces a detection signal if the one output signalexceeds a predetermined threshold.

[0011] The channelizing receiver further includes a signal amplitudecalculation unit for receiving the output signals and the detectionsignals. The signal amplitude calculation unit starts an initial timingperiod in response to the receipt of one of the detection signalsindicating detection of an electromagnetic signal and produces amagnitude signal providing the magnitude during the initial timingperiod of the output signal to which the one detection signalcorresponds.

[0012] The channelizing receiver also includes a channel to channelarbitration unit for receiving the magnitude signal and a first othermagnitude signal from a first other channel receiver of the channelizingreceiver produced in response to the first other channel receiver'sdetection of the electromagnetic signal during the initial timing periodwithin a first other frequency range being monitored by the first otherchannel receiver. The channel to channel arbitration unit compares themagnitude signal and the first other magnitude signal, and if the firstother magnitude signal is greater than the magnitude signal, inhibitsthe transmission from the channel receiver of data responsive to the onedetection signal.

[0013] The magnitude signal preferably provides the peak amplitudereached during the initial timing period by the output signal, and theplurality of filters preferably comprises a plurality of low passfilters having different cut-off frequencies. The electromagneticsignals preferably are radio frequency signals.

[0014] The channel to channel arbitration unit also preferably isadapted for receiving a second other magnitude signal from a secondother channel receiver of the channelizing receiver produced in responseto the second other channel receiver's detection of the electromagneticsignal during the initial timing period within a second other frequencyrange being monitored by the second other channel receiver, comparingthe magnitude signal with the second other magnitude signal, and if oneor both of the first other magnitude signal and the second othermagnitude signal is greater than the magnitude signal, inhibiting thetransmission from the channel receiver of the data.

[0015] The signal amplitude calculation unit preferably also is adaptedfor initiating an additional timing period in response to the onedetection signal, identifying a group of the threshold detectorsproducing detection signals during the additional timing period andproducing a peak amplitude signal providing the peak amplitude reachedduring the additional timing period by the output signal correspondingto the detection signal produced by the threshold detector of the groupassociated with the low pass filter having the lowest cut-off frequency.

[0016] Each channel receiver preferably also includes a bandwidth andfrequency estimation unit for receiving the peak amplitude signal and afirst other peak amplitude signal from the first other channel receiverproduced in response to the first other channel receiver's detection ofthe electromagnetic signal during the additional timing period, and forproducing an estimation signal providing an estimate of the frequencyand bandwidth of the electromagnetic signal based upon the peakamplitude signal and the first other peak amplitude signal.

[0017] The bandwidth and frequency estimation unit preferably is furtheradapted for receiving a second other peak amplitude signal from a secondother channel receiver of the channel receiver produced in response tothe second other channel receiver's detection of the electromagneticsignal during the additional timing period within a second otherfrequency range being monitored by the second other channel receiver,and producing the estimation signal based upon the peak amplitudesignal, the first other peak amplitude signal and the second other peakamplitude signal.

[0018] The signal amplitude calculation unit also preferably is adaptedfor identifying the peak amplitude by identifying a predetermined numberof consecutive samples of the one output signal having values less thanthe peak amplitude.

[0019] In another aspect, the present invention provides a method fordetecting an electromagnetic signal falling within a frequency band. Themethod includes providing a channelizing receiver having a plurality ofchannels with a bandpass filter for transmitting signals within asegment of the frequency band. The method further includes providing foreach channel a channel processor for receiving the signals, producing adetection signal indicating the detection of the electromagnetic signaland producing a magnitude signal indicating the magnitude of theelectromagnetic signal.

[0020] The method further includes identifying within a predeterminedtime period a group of the channel processors producing the detectionsignals and comparing for the group the magnitude signals correspondingto the detection signals to identify the highest magnitude signal. Theprocess also includes transmitting for the group from the channelizingreceiver data corresponding to one of the detection signals only if theone detection signal is associated with the highest magnitude signal.

[0021] The method preferably further includes assessing the relativemagnitudes of the magnitude signals of the group and, based upon theserelative magnitudes, providing an estimate of the frequency andbandwidth of the electromagnetic signal. The data preferably includesthis estimate and information identifying the beginning of a pulse ofthe electromagnetic signal and the end of the pulse. The electromagneticsignal preferably is a radio frequency signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIGS. 1A, 1B and 1C are a block diagram of a channelizing receiverin accordance with the present invention.

[0023]FIG. 2 is a block diagram of a wideband channelizing receiver inaccordance with the present invention.

[0024]FIG. 3 is a block diagram of a narrowband channelizing receiver inaccordance with the present invention.

[0025]FIG. 4 is a block diagram of the left-side components of a channelprocessor for one channel receiver of the channelizing receivers ofFIGS. 2 and 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] A channelizing receiver 101 in accordance with the presentinvention is shown in FIGS. 1A, 1B and 1C. For ease of description,channelizing receiver 101 is shown in these figures with only fourchannel receivers, namely, channel receiver A, channel receiver B,channel receiver C and channel receiver D. The components of each ofthese channel receivers are correspondingly labeled with these letters.For most applications, however, channelizing receiver 101 will containmore than only four channel receivers (e.g., 16 channel receivers, 20channel receivers, etc.).

[0027] Channel receivers A, B, C and D all separately monitor onesegment of a band of frequencies within the electromagnetic spectrum.For most applications, the segments are contiguous and the band offrequencies is continuous within the RF Spectrum. However, if desired,the segments can be separated, and the band of frequencies can bediscontinuous. The number of channel receivers employed in channelizingreceiver 101, and the bandwidth of each channel receiver, can beselected to correspond with the frequency range of the electromagneticsignals being monitored and the expected magnitude of these signals.

[0028] As shown in FIGS. 1A, 1B and 1C, each channel receiver ofchannelizing receiver 101 contains a plurality of left-side componentsand a plurality of right-side components. Orthogonally polarizedantennas (not shown) receive electromagnetic emissions within thefrequency band being monitored. Both left and right polarizedelectromagnetic signals are then detected by the channelizing receiver101. The particular portion of the frequency spectrum being monitoredcan be selected by adjusting the frequency of a local oscillator (notshown) prior to channelizing receiver 101. The left-side componentsreceive one of the orthogonally polarized electromagnetic signals, andthe right-side components receive the other orthogonally polarizedelectromagnetic signal. The left-side orthogonally polarizedelectromagnetic signals and the right-side orthogonally polarizedelectromagnetic signals are transmitted to, respectively, bufferamplifiers 103 and 105. The outputs from these buffer amplifiers aretransmitted to the front ends of the respective sides of the channelreceivers.

[0029] As further shown in FIG. 1A, the output of buffer amplifier 103is transmitted to analog bandpass filters 113, 111, 109 and 107 for,respectively, the left-side components of channel receiver A, channelreceiver B, channel receiver C and channel receiver D. In a similarmanner, the output of buffer amplifier 105 is transmitted to analogbandpass filters 115, 117, 119 and 121 for, respectively, the right-sidecomponents of channel receiver A, channel receiver B, channel receiver Cand channel receiver D.

[0030] These bandpass filters preferably are three-pole analog bandpassfilters with equal frequency and roll-off characteristics. Each bandpassfilter defines the particular monitoring center frequency and frequencyrange or bandwidth (e.g., a range of 32 MHz, 250 MHz, etc.) of eachchannel receiver with which the bandpass filter is associated. Eachbandpass filter passes electromagnetic signals within its designatedfrequency range and rejects electromagnetic signals outside of thisrange.

[0031] As further shown in FIG. 1A, the outputs from left-side analogbandpass filters 113, 111, 109 and 107 are transmitted to, respectively,left-side log detectors 129, 127, 125 and 123. In a similar manner, theoutputs from right-side analog bandpass filters 115, 117, 119 and 121are transmitted to, respectively, right-side log detectors 131, 133, 135and 137. The electromagnetic input signals to the log detectorsgenerally are high density pulses having narrow widths and largevariations in amplitude. The log detectors condense these largevariations into smaller, manageable variations using a logarithmictransfer function. The voltage amplitude of each log detector's outputanalog signal (called a video signal) is proportional to the power ofits input signal in decibels (dBs). Such log detectors are well known inthe art. The dynamic range of each log detector preferably is at least60 dB. This range provides sufficient sensitivity for each channelreceiver to effectively monitor a wide spectrum of electromagneticfrequencies for coincident signals in a dense environment. Dependingupon the width of the electromagnetic spectrum being monitored, thebandwidths of these video output signals preferably are betweenapproximately 16 MHz and 20 MHz. Of course, detectors with otherbandwidths may be employed within the scope of the invention.

[0032] As further shown in FIG. 1A, the outputs from left-side logdetectors 129, 127, 125 and 123 are transmitted to, respectively,left-side analog to digital (A/D) converters 145, 143, 141 and 139. In asimilar manner, the outputs from right-side log detectors 131, 133, 135and 137 are transmitted to, respectively, right-side A/D converters 147,149, 151 and 153. These A/D converters sample the analog video signalsfrom the log detectors and provide digital signals representative ofthese analog signals. The sampling rate and resolution of these A/Dconverters preferably are, respectively, approximately 62.5 millionsamples per second and 8 bits. Of course, other sampling rates andresolutions may be employed within the scope of the invention.

[0033] The left-side and right-side digitized, video signals from theA/D converters for channel receivers A, B, C and D are combined by,respectively, baseband combiners 155, 157, 159 and 161. These basebandcombiners sum for each channel the channel's left-side and right-sidedigital samples. These samples, as indicated above, represent therespective orthogonal components of each video signal. The basebandcombiners and all subsequent functional elements are preferably fieldprogrammable gate arrays (FPGAs) or application specific integratedcircuits (ASICs).

[0034] The summing step performed by the baseband combiners, if desired,can be omitted. In that event, the orthogonal components for only theleft side of each channel, or the orthogonal components for only theright side of each channel, can be processed separately. In yet afurther alternative, the orthogonal components for both sides of eachchannel can be processed in parallel without summing.

[0035]FIG. 1B illustrates further components of the channel receivers ofchannelizing receiver 101. As shown in this figure, the output signalsfrom baseband combiners 155, 157, 159 and 161 are transmitted to,respectively, finite impulse response (FIR) low pass filters 162, 163,164 and 165. Each FIR filter has a sequential series of outputs, andeach of these outputs transmits a narrower band of frequency signals,i.e., each has a lower cut off frequency. For example, as shown in FIG.1B, each FIR low pass filter preferably has six taps, and the cut offfrequency of each tap preferably is one octave below (i.e., one-half)the cut off frequency of each next wider tap. These cut off frequencies,and the other coefficients of these filters, preferably are adjusted todetect short pulse, wideband RF emissions. A preferable set of cut offfrequencies for these six taps is, e.g., 16 MHz, 8 MHz, 4 MHz, 2 MHz, 1MHz and 0.5 MHz. These cut off frequencies, and the characteristics ofeach FIR low pass filter, preferably are modifiable through fieldprogrammable gate arrays. In lieu of FIR filters, other low pass filtersmay be employed within the scope of the invention, e.g., infiniteresponse filters. FIR filters are preferred, however, because of theirenhanced stability.

[0036] As further shown in FIG. 1B, the six output signals from FIRfilters 162, 163, 164 and 165 are transmitted to, respectively,multiplexers 166, 167, 168 and 169. Each multiplexer preferably has fouroutputs, receives six inputs and is capable of selecting any of its sixinputs for transmission to any of these four outputs. Of course, othercombinations of inputs to outputs may be employed within the scope ofthe invention. The particular connections of inputs to outputspreferably also are field programmable.

[0037] The output signals from multiplexers 166, 167, 168 and 169 aretransmitted to, respectively, threshold detector groups 170, 171, 172and 173. Each threshold detector group preferably includes a separatethreshold detector for each output of the multiplexer with which it isassociated. Each threshold detector of each threshold detector group,therefore, receives an input from a different FIR low pass filter tap.The threshold level and detection criteria of these threshold detectorspreferably also are field programmable. The detection criteria includes,e.g., the number of samples above a particular threshold necessary toassert an output signal, the number of samples below this thresholdnecessary to de-assert this output signal, and the number of consecutivesamples that must occur with values below the output signal's mostrecent maximum to declare this maximum the true peak value. Theprogrammability of these detection criteria enables channelizingreceiver 101 to be adjusted to detect a broad range of electromagneticsignals with minimal false triggering.

[0038] Each threshold detector group also contains logic circuitry forperforming an arbitration process. This arbitration process occurs amongthe threshold detectors of a threshold detector group detecting a signaland the threshold detectors of adjacent threshold detector groups alsodetecting the signal. The arbitration process, discussed in detailbelow, chooses from among these threshold detectors a particularthreshold detector for transmitting an output signal to the analyzingreceiver (not shown).

[0039] As further shown in FIG. 1B, the output signals from thresholddetector groups 170, 171, 172 and 173 are transmitted to, respectively,frequency and bandwidth estimators 174, 175, 176 and 177. Pursuant tothe arbitration process, only one of these frequency and bandwidthestimators receives a signal from a threshold detector group andprovides, in response, an output signal to the analyzing receiver. Thefrequency and bandwidth estimators contain logic circuitry to provide,with this output signal, an estimation of the frequency and bandwidth ofthe detected signal within the detecting channel. This information isintended to facilitate the analyzing receiver's analysis of the receivedRF emissions. The process for providing this estimation is discussed indetail below.

[0040]FIG. 1C illustrates further components of the channel receivers ofchannelizing receiver 101. These further components operate in parallelto those shown in FIG. 1B. As shown in FIG. 1B, the output signals frombaseband combiners 155, 157, 159 and 161 also are transmitted to,respectively, FIR low pass filters 178, 179, 180 and 181. Like FIR lowpass filters 162, 163, 164 and 165, FIR low pass filters 178, 179, 180and 181 also preferably have a sequential series of output taps, e.g.,as shown in FIG. 1C, nine output taps, and each of these output tapstransmits a narrower band of frequency signals, i.e., has a lower cutoff frequency. Also, like FIR low pass filters 162, 163, 164 and 165,the cut off frequency of each tap preferably is one octave below the cutoff frequency of each wider tap. A preferable set of cut off frequenciesfor the nine taps of each low pass filter 178, 179, 180 and 181 is,e.g., 0.25 MHz, 0.125 MHz, 0.0625 MHz, 0.0313 MHz, 0.0156 MHz, 0.0078MHz, 0.0039 MHz, 0.0020 MHz and 0.0010 MHz. These cut off frequencies,and the coefficients of each FIR low pass filter, preferably also aremodifiable through field programmable gate arrays. Also, in lieu of FIRlow pass filters, other filters may be employed for this purpose, e.g.,infinite response filters.

[0041] As indicated above, the cut off frequencies of FIR low passfilters 162, 163, 164 and 165 (FIG. 1B), and the other characteristicsof these filters, preferably are adjusted to detect short pulse,wideband RF emissions. The cut off frequencies of FIR low pass filters178, 179, 180 and 181 (FIG. 1C), and the other characteristics of thesefilters, on the other hand, preferably are adjusted to detect longpulse, narrowband, or continuous wave (CW), RF emissions, i.e., RFemissions within a narrow bandwidth and having a far longer durationthan the short pulses falling within a wide bandwidth for which FIR lowpass filters 162, 163, 164 and 165 are designed to detect.

[0042] As further shown in FIG. 1C, the nine output signals from FIRfilters 178, 179, 180 and 181 are transmitted to, respectively,multiplexers 182, 183, 184 and 185. Unlike multiplexers 166, 167, 168and 169, however, each of multiplexers 182, 183, 184 and 185 has onlyone output. Each multiplexer is capable of selecting any one of its nineinputs for transmission to this one output. Of course, if desired, eachmultiplexer 182, 183, 184 and 185, like multiplexers 166, 167, 168 and169, can have a plurality of outputs and can select from among itsinputs a plurality of these inputs for transmission on these outputs.

[0043] The output signals from multiplexers 182, 183, 184 and 185 aretransmitted to, respectively, threshold detectors 186, 187, 188 and 189.Each of these threshold detectors is similar to one threshold detectorof threshold detector groups 170, 171, 172 and 173. Like the thresholddetectors of these threshold detector groups, therefore, the thresholdlevel and detection criteria of threshold detectors 186, 187, 180 and189 also preferably are field programmable. These detection criteriainclude, e.g., the number of samples above a particular thresholdnecessary to assert an output signal, the number of samples below thisthreshold necessary to de-assert this output signal, and the number ofconsecutive samples that must occur with values below the outputsignal's most recent maximum to declare this maximum the true peakvalue. The output signals from these threshold detectors are transmittedto the analyzing receiver.

[0044] As discussed above, threshold detector groups 170, 171, 172 and173 each include logic circuitry for conducting a process of arbitrationamong the threshold detectors of the group and the threshold detectorsof the groups adjacent to the group. This arbitration process results inthe transmission of signal data to the analyzing receiver from only thechannel threshold detector group where the majority of the signal'sspectral energy is located. As a result, the analyzing receiver does notwaste its resources in analyzing numerous signals generated by thechannel receivers in response to a single detected signal. The logiccircuitry for this arbitration process preferably comprises fieldprogrammable gate arrays (FPGAs) or application specific integratedcircuits (ASICs).

[0045] A threshold detector of threshold detector groups 170, 171, 172and 173 generates a detection signal in response to the detector'sreceipt of a predetermined number of samples from the FIR low passfilter tap to which the detector is connected (FIR signal) above thedetector's predetermined threshold. Requiring a predetermined number ofsamples above this threshold before generating a detection signalminimizes the occurrences of false detections from noise andmiscellaneous RF background signals. Each detection signal from athreshold detector is transmitted to the logic circuitry of the channelreceiver with which the threshold detector is associated and also to thelogic circuitry of the channel receivers adjacent to this channelreceiver. The first threshold detector to indicate detection of a signalinitiates predetermined timing periods for conducting two levels ofarbitration. The first level of arbitration is among threshold detectorgroups of adjacent channels for the purpose of identifying the channelfrequency band where the received RF emission is most likely located.The second level of arbitration is among the threshold detectors withinan individual channel's threshold detector group. In this second levelof arbitration, the purpose is to identify the threshold detectorassociated with the most optimal FIR LPF cutoff frequency for estimatingthe frequency and bandwidth of the received RF emission signal.

[0046] If a channel receiver is located centrally within the frequencyband being monitored by channelizing receiver 101 (e.g., channelreceiver B or C), the adjacent channel receivers are the channelreceiver monitoring frequencies immediately above and below thesemonitoring frequencies. On the other hand, if a channel receiver ismonitoring frequencies at the lower end of the frequency band beingmonitored by channelizing receiver 101 (e.g., channel receiver A) or theupper end of the frequency band being monitored by channelizing receiver101 (e.g., channel receiver D), the adjacent channel receivers are,respectively, the two contiguous channel receivers monitoringfrequencies immediately above these monitoring frequencies and the twocontiguous channel receivers monitoring frequencies immediately belowthese monitoring frequencies (e.g., in each case, channel receivers Band C).

[0047] During the first timing period for the first level ofarbitration, the channel group containing the initiating thresholddetector will determine the peak value of the FIR signal associated withthat detector. The peak value is determined from an incoming series ofFIR data samples by continually seeking to identify incoming sampleswith a maximum value and only declaring that the last maximum sample isthe peak value after a predetermined number of consecutive samples havebeen received with values less than the maximum. Also during this firsttiming period, the channel threshold detector groups immediatelyadjacent to the initiating channel group will each determine the peakvalue of the FIR signal received by the threshold detector that firstgenerates a detection signal. The peak value for each adjacent channelthreshold detector group is determined in the same manner as for theinitiating channel. By the end of this timing period, the peak FIRsignal value for each channel triggered by the detected signal isdetermined and communicated to each channel's respective adjacentchannel pair.

[0048] During the second timing period for the second level ofarbitration, each threshold detector group in which at least onethreshold detector has been triggered determines the peak value of theFIR signal received by the triggered threshold detector associated withthe lowest cut off frequency tap. Peak values are determined in the samemanner as previously described. By the end of second level arbitrationtime period, this peak FIR signal for each channel is determined andcommunicated to each channel's respective adjacent channel pair.

[0049] When the first level of arbitration values are received by achannel or when the end of the first time period has occurred, a channelwill determine if it has won arbitration. If a channel does not receivea peak value from an adjacent channel by the end of the first timeperiod, the peak value for that channel is assumed to be zero. Thewinner of the first level of arbitration preferably is the channel whichreceived the maximum peak FIR signal compared to all respective adjacentchannels during the timing period.

[0050] The channel that determines it has won the first level ofarbitration generates a signal to the analyzing receiver indicating apulse RF emission event has occurred within the frequency range of thatchannel. This channel then proceeds to use the values from the secondlevel of arbitration determined for that channel and received fromadjacent channels to estimate signal frequency and bandwidth. A channelthat determines it has lost the first level of arbitration ignores thesecond level arbitration values, clears itself and provides no outputsignal to the analyzing receiver.

[0051] As indicated above, each channel receiver conducts arbitrationsindependently of every other channel receiver. The results ofarbitration are dependent on the data exchanged in parallel betweenadjacent channels. As a result, a detected signal will result in severalthreshold detector groups independently conducting arbitrations amongthe detectors of their groups and their adjacent groups. Theseindependent arbitrations are parallel and nearly simultaneous. If achannel receiver conducting an arbitration loses the arbitration to oneof its adjacent channel receivers, therefore, an arbitration conductedby one of those adjacent channel receivers, or one of the channelreceivers adjacent to one of those adjacent channel receivers, etc.,eventually will win an arbitration and provide a signal to the analyzingreceiver. Because of these multiple, independent arbitrations, however,this winning channel receiver is the channel receiver monitoring thefrequency band most closely related to the frequency of the detected RFsignal.

[0052] For example, referring to the threshold detectors of FIG. 1B, ifthreshold detector B2 detects an input signal exceeding itspredetermined threshold for the required number of samples, thresholddetector B2 generates a detection signal which is transmitted to thelogic circuitry of this detector's group, namely, group 171, and thethreshold detector groups adjacent to this detector group, namely,detector groups 170 and 172. In each case, the logic circuitry's receiptof this first detection signal initiates an independent timing periodfor the logic circuitry of the group to conduct two levels ofarbitration among the detectors of the group and the detectors of thegroups adjacent to the group. In the case of threshold detector group171, e.g., this detection signal initiates timing periods forarbitration among threshold detectors B1, B2, B3 and B4 and also amongthe adjacent threshold detectors, namely, threshold detectors A1, A2, A3and A4 and threshold detectors C1, C2, C3 and C4.

[0053] During the first level timing period, the logic circuitry forthreshold detector group 171 determines the peak FIR signal received bythreshold detector B2. During this first level timing period, the logiccircuitry of threshold detector groups 170 and 172, triggered by thelogic circuitry of threshold detector group 171, also execute identicalarbitration among the detectors of their respective adjacent groups. Forexample, if, during this timing period, the first threshold detector ofthreshold detector group 170 providing an output signal is thresholddetector A3 and the first threshold detector of threshold detector group172 providing an output signal is threshold detector C1, the logiccircuitry of these groups will determine the peak FIR signal receivedby, respectively, threshold detectors A3 and C1.

[0054] During the second level timing period, the logic circuitry forthreshold detector group 171 determines whether threshold detectors B3and/or B4 also provide a detection signal. These detectors areassociated with a tap of the FIR low pass filter 163 having successivelylower cutoff frequencies than that of the tap with which thresholddetector B2 is associated. Dependent on preset limits, the logiccircuitry will select the peak FIR signal received from the thresholddetector associated with the lowest cutoff frequency available withinthis second timing period. For example, if threshold detector B4provides an output signal whose peak value is determinable within thesecond timing period, then that value will be output to adjacent channelgroups 170 and 172 as the second level arbitration for group 171. Ifneither threshold detectors B3 or B4 generates a signal within thesecond timing period, then the peak value of threshold detector B2 isoutput at the second level arbitration for group 171. If during thesecond timing period, threshold detectors A4 and C4 (threshold detectorswith the lowest cutoff frequencies associated with threshold detectorgroups 170 and 172, respectively) provide output signals whose peakvalues are determinable within the second timing period, then thesevalues are output to adjacent channel groups as the second levelarbitration values for groups 170 and 172, respectively.

[0055] At the conclusion of the arbitration timing periods, the logiccircuitry for threshold detector group 171 receives the peak values fromamong the detectors of this initiating detector group and adjacentdetector groups 170 and 172. For this example, as indicated above, thefirst level arbitration values are from threshold detectors B2, A3 andC1. Also, assume that the second level arbitration values are fromthreshold detectors B4, A4 and C4. The winner of the arbitration amongthe three channel receivers in this example with respect to group 171 isthe channel receiver having the highest first level arbitration peak FIRsignal. If threshold detector group 171 wins this arbitration, thenchannel receiver B provides an output signal to the analyzing receiverand proceeds to estimate frequency and bandwidth using the second levelarbitration values from detector groups 170, 171 and 172. Additionally,detector groups 170 and 172 halt further processing and their respectivechannel logic circuitries are cleared to receive the next pulse signal.Therefore, channel receivers A and C provide no output signal to theanalyzing receiver.

[0056] As discussed above, frequency and bandwidth estimators 174, 175,176 and 177 include logic circuitry for providing to the analyzingreceiver an estimation of the frequency and bandwidth of the detectedsignal to facilitate the efficiency of the analyzing receiver's analysisof this signal. This logic circuitry also preferably comprises fieldprogrammable gate arrays (FPGAs) or application specific integratedcircuits (ASICs).

[0057] A frequency and bandwidth estimator, like a threshold detectorgroup, provides a signal to the analyzing receiver only if the channelreceiver with which the frequency and bandwidth estimator is associatedwins an arbitration. If a channel receiver loses the arbitration,processing by the channel receiver's associated frequency and bandwidthestimator is not initiated.

[0058] The frequency and bandwidth estimator of a channel receiverwinning arbitration receives the second level arbitration values of thewinning channel receiver and the two adjacent losing channel receivers.Since the frequency bandwidth monitored by the winning channel receiveris known, the identity of this channel receiver in itself provides acoarse estimate of the detected signal's frequency.

[0059] Using the three second level arbitration values, the frequencyand bandwidth estimator consults a lookup table. Depending upon themagnitude of the values, this lookup table provides information moreprecisely indicating the detected signal's frequency within thebandwidth monitored by the winning channel receiver. For example, assumedetector B2 of detector group 171 is the winner in an arbitration amongthe threshold detectors of adjacent groups 170 and 172. Assume also thatthe peak values from threshold detectors B4, A4 and C4 were selectedduring the second level arbitration for groups 171, 170 and 172,respectively. Also, assume that the magnitude of the value generated bythreshold detector A4 is relatively greater than the magnitude of thevalue generated by threshold detector C4. Under these circumstances, thelookup table will indicate that the detected signal's frequency withinthe bandwidth monitored by channel receiver B leans toward the frequencybeing monitored by channel receiver A. On the other hand, if themagnitude of the value generated by threshold detector C4 is relativelygreater than the magnitude of the value generated by the thresholddetector A4, then the lookup table will indicate that the detectedsignal's frequency within the bandwidth monitored by channel receiver Bleans toward the frequency band monitored by channel receiver C. A copyof this lookup table is stored within a memory of the frequency andbandwidth estimator of each channel receiver.

[0060] A second lookup table also is stored within the memory of thefrequency and bandwidth estimator of each channel receiver. Using againthe three second level arbitration values, the frequency and bandwidthestimator uses this second lookup table to provide an indication of thedetected signal's bandwidth within the frequency band monitored by thewinning channel receiver. In a manner similar to that for estimatingfrequency, this second lookup table indicates that the bandwidth of thedetected pulse is relatively narrow, if the magnitude of the secondlevel arbitration values of the adjacent channel receivers arerelatively small in comparison to the magnitude of the second levelarbitration value generated by the winning channel receiver. On theother hand, if the magnitudes of the second level arbitration values ofthe adjacent channel receivers are relatively equal to the magnitude ofthe second level arbitration values generated by the winning channelreceiver, the second lookup table will indicate that the bandwidth ofthe detected pulse is relatively wide.

[0061] The frequency and bandwidth estimator for a winning channelreceiver transmits, via an interface (not shown), a digital signal tothe analyzing receiver providing these estimates of the detectedsignal's frequency and bandwidth. This interface also transmits a signalindicating the detected signal's start of pulse and end of pulse. Thedetected signal's start of pulse is based upon the signal generated bythe detector winning first level arbitration. The detected signal's endof pulse is based upon the time at which the detected signal falls belowthis winning detector's predetermined threshold for the requisite numberof samples. Finally, this interface also transmits a digital signal tothe analyzing receiver providing the peak amplitude of the detectorwinning first level arbitration.

[0062] A block diagram for a wideband channelizing receiver 202 inaccordance with the present invention is shown in FIG. 2. Widebandchannelizing receiver 202 contains 16 channel receivers. Each of thesechannel receivers is configured to monitor one contiguous segment of acontinuous 4000 MHz bandwidth. The bandwidth of each channel receiver ofchannelizing receiver 202, therefore, is 250 MHz.

[0063] Each channel receiver of channelizing receiver 202 contains achannel processor 211, two bandpass filters 209 and two bufferamplifiers 207. The buffer amplifiers provide inputs to the bandpassfilters. Each of these channel processors contains a set of left-sidecomponents and a set of right-side components. In a manner similar tochannelizing receiver 101, polarizing antennas detect signalstransmitted to channelizing receiver 202 and generate orthogonallypolarized electromagnetic signals. The left-side components of thechannel processors receive one of these orthogonally polarizedelectromagnetic signals, and the right-side components receive the otherorthogonally polarized electromagnetic signal. The left-sideorthogonally polarized electromagnetic signals and the right-sideorthogonally polarized electromagnetic signals are transmitted to,respectively, buffer amplifiers 201 and 241. The output signals frombuffer amplifiers 201 and 241 are transmitted to, respectively, inputattenuators 263 and 261. These input attenuators enable control of theamplitudes of these output signals in steps of 0.5 dB.

[0064] The output signals from input attenuators 263 and 261 aretransmitted to, respectively, buffer amplifiers 203 and 243, and theoutput signals from these buffer amplifiers are transmitted to,respectively, splitters 205 and 245. Each splitter has two outputs. Theoutputs for splitter 205 are transmitted via a series of 3-way couplersto the inputs of buffer amplifiers 207 which are connected to the inputsof bandpass filters 209 transmitting signals to the left-side componentsof the channel receivers. The outputs from splitter 245, on the otherhand, are transmitted via a series of 3-way couplers to the inputs ofbuffer amplifiers 207 which are connected to the inputs of bandpassfilters 209 transmitting signals to the right-side components of thechannel receivers.

[0065] The outputs from channel processors 211 are transmitted to dataacquisition equipment 215. Data acquisition equipment 215 collects theoutputs from the various channel processors and transmits these outputsto a resource allocation system (not shown). The resource allocationsystem transmits the data to other systems for further analysis, ifwarranted, such as an analyzing receiver. These other systems can modifythe settings of all predetermined values including filter coefficients,threshold levels, detection criteria, timeouts, lookup tables and theinput attenuation settings by communicating requests via the usercontrol terminal 247. The outputs to the data acquisition equipment 215include, as discussed above in connection with channelizing receiver101, signals from the channel processors winning arbitration providingestimations of a detected signal's amplitude, frequency and bandwidth,as well as a pulse signaling the starting time and ending time of thedetected signal. The various field programmable coefficients forconfiguring the components of channelizing receiver 202, discussed abovein connection with channelizing receiver 101, are entered on usercontrol terminal 247 and transmitted from this terminal to channelizingreceiver 202 on configuration parameter control bus 251. User controlterminal 247 may be, e.g., a personal computer, special purposecomputer, programmed microprocessor or any other device capable ofreceiving these coefficients from a user and transmitting them to thechannel processors.

[0066] A narrowband channelizing receiver 302 in accordance with thepresent invention is shown in FIG. 3. Narrowband channelizing receiver302 is functionally similar to wideband channelizing receiver 202. Thebandwidth of each channel receiver, however, is only 32 MHz. Narrowbandchannelizing receiver 302, therefore, monitors a continuous bandwidth ofonly 512 MHz.

[0067] As shown in FIG. 3, the output signals from input attenuators 361and 363 are transmitted to, respectively, 4-way splitters 303 and 349.The four outputs from 4-way splitter 303 are transmitted via bufferamplifiers 305 and then again divided by four before input to bandpassfilters 307. These 16 bandpass filters transmit signals to the left-sidecomponents of the 16 channel processors. The four outputs from 4-waysplitter 349, on the other hand, are transmitted via buffer amplifiers351 and then again divided by four before input to bandpass filters 317.These 16 bandpass filters transmit signals to the right-side componentsof the 16 channel processors.

[0068] The channel processors for channelizing receivers 202 and 302each contain a plurality of left-side components and a plurality ofright-side components. A block diagram for the left-side components of asingle channel processor N for these channelizing receivers is shown inFIG. 4. The right-side components for the channel processor areidentical.

[0069] The left-side and right-side digitized, video data samples fromthe log detectors and A/D converters (not shown) are transmitted tocombiner 411. If combiner 411 is enabled, the channel's left-side andright-side digital samples are summed and further processed by only thechannel's left-side components. In that event, the channel's right-sidecomponents are disabled. On the other hand, if combiner 411 is disabled,and the channel's left-side and right-side components are enabled, thenthe channel's left-side signals are separately processed by itsleft-side components, and the channel's right-side signals areseparately processed by its right-side components. Arbitration amongadjacent channels for the channel's left-side components is with respectto only the adjacent channel's left-side components and vice versa.

[0070] The output signal from combiner 411 is transmitted through aseries of FIR low pass filters, namely, FIR low pass filters 435, 437,439, 441, 443, 445, 447, 449, 451, 453, 455, 457, 459, 461 and 463. Thecut off frequencies of these FIR low pass filters decrease one octave ata time. These cut off frequencies are 16 MHz, 8 MHz, 4 MHz, 2 MHz, 1MHz, 0.5 MHz, 250 KHz, 125 KHz, 62 KHz, 31 KHz, 15 KHz, 8 KHz, 4 KHz, 2KHz and 1 KHz. The coefficients for these FIR low pass filters arestored in internal registers and are programmable from user controlterminal 247 (FIGS. 2 and 3). FIR low pass filters 435, 437, 439, 441,443 and 445 are used for the detection of short pulse, wideband RFemissions and transmit their outputs to FIR output selector 465. FIR lowpass filters 447, 449, 451, 453, 455, 457, 459, 461 and 463 are used forthe detection of long pulse, narrowband, or continuous wave (CW), RFemissions, and transmit their outputs to FIR output selector 467.

[0071] LPF output selector 465 receives six inputs and transmits fouroutputs. A pulse select command from, e.g., user control terminal 247 orthe analyzing receiver, causes LPF output selector 465 to select whichof these six inputs are transmitted to the selector's four outputs. LPFoutput selector 467, on the other hand, receives nine inputs andtransmits only one output. A CW select command from, e. g., these samesources causes this selector to select which of these nine inputs istransmitted to this one output.

[0072] The four low pass filter outputs from LPF output selector 465,namely, LPF1, LPF2, LPF3, and LPF4, are transmitted to, respectively,pulse data capture unit 1, pulse data capture unit 2, pulse data captureunit 3 and pulse data capture unit 4. The one output from LPF outputselector 467 is transmitted to pulse data capture unit 5. These LPFsignals are a clocked series of digital samples which are transmitted tothe pulse data capture units at the frequency of the system's internalclock as decimated by the FIR LPF filters. The thresholds and detectioncriteria for these pulse data capture units also are stored in registersand are transmitted from, e.g., user control terminal 247. Thesedetection criteria include the data capture unit's threshold value, thenumber of samples above this threshold value necessary to produce asignal detection (M value) and the number of samples below thisthreshold value necessary to terminate a signal detection (P value).

[0073] Each pulse data capture unit monitors its input for digitalsamples above the unit's threshold value. If M consecutive samples occurabove the unit's threshold value, the pulse data capture unit asserts apre-detect signal (PREDET). Pulse data capture units 1, 2, 3 and 4 willassert, under these circumstances, PREDET1, PREDET2, PREDET3 andPREDET4, respectively. The first pulse data capture unit asserting aPREDET signal in response to a detected signal is designated the “targetunit.” This PREDET signal is transmitted to pulse signal amplitude (SA)calculation unit 477. This initial PREDET signal causes pulse SAcalculation unit 477 to transmit a pre-pulse detect (PPD) signal tochannel to channel arbitration unit 483 and to bandwidth and frequencyestimation unit 491.

[0074] In addition to channel to channel arbitration unit 483, the PPDsignal from pulse SA calculation unit 477 also is transmitted to channelN−1 output port interface 485 and channel N+1 output port interface 489of output port interfacing 417. These output port interfaces transmitthe PPD signal to the channel to channel arbitration units of channelprocessor N−1 and channel processor N+1, respectively. Channel tochannel arbitration unit 483 also receives PPD signals from channelprocessors N−1 and N+1 via channel N−1 input port interface 413 andchannel N+1 input port interface 415, respectively.

[0075] The target pulse data capture unit's assertion of its PREDETsignal causes pulse SA calculation unit 477 to begin monitoring delayedsamples of the LPF data (LPF delay data) transmitted by the target pulsedata capture unit for the peak amplitude of the detected signal (PDSA).Pulse data capture units 1, 2, 3 and 4 transmit to pulse SA calculationunit 477 LPF1 delay data, LPF2 delay data, LPF3 delay data and LPF4delay data, respectively. The peak amplitude value (PDSA) is determinedby the process of continuously monitoring the LPF delay data samplesfrom a pulse data capture unit for maximum values and declaring the lastmaximum value the peak only when immediately followed by a consecutiveseries of lower value samples equal to the number value set by thepredetermined pulse SA timeout. The pulse SA timeout also is stored in aregister and is programmable from, e.g., user control terminal 247.

[0076] The target pulse data capture unit's assertion of its PREDETsignal also causes pulse SA calculation unit 477 to transmit an inhibitsignal to each pulse data capture unit having a number lower than thatof the target unit. These lower numbered units receive LPF data from anFIR low pass filter having a cut off frequency higher than that of theFIR low pass filter with which the target unit is associated. The signalamplitudes of the LPF data received by these lower numbered pulse datacapture units are not used in the first level arbitration process or inthe second level arbitration process for the subsequent estimation ofthe detected signal's bandwidth and frequency. Further monitoring andcalculation of the LPF delay data from these lower numbered units,therefore, are unnecessary.

[0077] Monitoring of the LPF delay data from the target pulse datacapture unit for the peak amplitude of the detected signal (PDSA)continues until this peak amplitude is identified or the target pulsedata capture unit's PREDET signal becomes inactive. In the latter case,the PDSA is set to the maximum amplitude identified at the time that thePREDET signal becomes inactive. Upon identifying the PDSA, pulse SAcalculation unit 477 transmits to channel to channel arbitration unit483 the PDSA and a signal indicating that the PDSA is valid (PDSA validsignal). The PDSA and PDSA valid signals also are transmitted to channelN−1 output port interface 485 and channel N+1 output port interface 489.These output port interfaces transmit the PDSA and PDSA valid signals tothe channel to channel arbitration units of channel processors N−1 andN+1, respectively. Channel to channel arbitration unit 483 also receivesPDSA and PDSA valid signals from channel processor N−1 and channelprocessor N+1via channel N−1 input port interface 413 and channelN+1input port interface 415, respectively.

[0078] Assertion of the target pulse data capture unit's PREDET signalalso initiates the ESTSA timeout. During this timing period, the pulseSA calculation unit 477 also monitors the PREDET signals from the pulsedata capture units having a number higher than that of the target unit.If any of these pulse data capture units asserts its PREDET signal, thepulse SA calculation unit 477 monitors the LPF delay data received fromthe respective pulse data capture unit to identify the peak amplitude ofthese data. This monitoring is performed in the same manner as for theLPF delay data from the target pulse data capture unit to determine thisunit's peak amplitude. This process continues for each of the highernumbered pulse data capture units until either the expiration of theESTSA timeout or the maximum amplitude of the LPF data received by thepulse data capture unit having the highest allowed number is identified(ESTSA). Upon identifying the ESTSA, pulse SA calculation unit 477transmits the ESTSA to bandwidth and frequency estimation unit 491.Pulse SA calculation unit 477 also transmits to bandwidth and frequencyestimation unit 491 a signal indicating that the ESTSA is valid (ESTSAvalid signal). The ESTSA and ESTSA valid signals also are transmitted tochannel N−1 output port interface 485 and channel N+1 output portinterface 489. These output port interfaces transmit the ESTSA and ESTSAvalid signals to the bandwidth and frequency estimation units of channelprocessors N−1 and N+1, respectively. Bandwidth and frequency estimationunit 491 also receives ESTSA and ESTSA valid signals from channelprocessors N−1 and N+1 via channel N−1 input port interface 413 andchannel N+1 input port interface 415, respectively. The ESTSA timeoutand highest allowed ESTSA pulse data capture unit value are stored in aregister and are programmable from, e.g., user control terminal 247.

[0079] The one low pass filter output from LPF output selector 467 istransmitted to pulse data capture unit 5. Like pulse data capture units1-4, pulse data capture unit 5 monitors its input for LPF5 data abovethe unit's predetermined threshold value. If M consecutive samples ofLPF5 data occur above this threshold value, pulse data capture unit 5asserts a continuous wave detection signal (CD). The CD signal istransmitted to CW SA calculation unit 481 and also to channel N outputport interface 487 of output port interfacing 417. This CD signal causesCW SA calculation unit 481 to begin monitoring delayed samples of LPF5data from pulse data capture unit 5 for the peak amplitude of thedetected continuous wave signal (CWSA). The CWSA is determined bycontinuously monitoring the LPF5 delay data samples from pulse datacapture unit 5 for maximum values and declaring the last maximum valuethe peak only when immediately followed by a consecutive series of lowervalue samples equal to a predetermined number (CW SA timeout). Uponidentification of the CWSA, CW SA calculation unit 481 transmits aninhibit signal to pulse data capture unit 5 to prevent further assertionof the CD signal. If the CD signal becomes inactive before this maximumamplitude is determined, the CWSA is set to the maximum amplitudeidentified at the time that the CD signal becomes inactive. The CW SAtimeout also is stored in internal registers and is programmable from,e.g., user control terminal 247. Upon identifying the CWSA, CW SAcalculation unit 481 transmits the CWSA to channel N output portinterface 487 of output port interfacing 417. CW SA calculation unit 481also transmits to output port interface 487 a signal indicating that theCWSA is valid (CWSA VALID).

[0080] Channel to channel arbitration unit 483 remains in a standbycondition until a PPD signal from either pulse SA calculation unit 477,channel N−1 input port interface 413 or channel N+1 input port interface415 is received. Upon receipt of a PPD signal from any of these sources,channel to channel arbitration unit 483 initiates a process ofarbitration among channel processors N, N−1 and N+1. In accordance withthis process, channel to channel arbitration unit 483 loads a digitaltimer with the programmable value PPD ARB timeout and a second digitaltimer with the programmable value SA ARB timeout. Like the otherprogrammable timeout values of the channel processors, these timeoutvalues also are stored in internal registers and may be transmitted tothe channel processor from, e.g., user control terminal 247.

[0081] PPD ARB timeout and SA ARB timeout both define timing periods.Upon receipt of a PPD signal from either pulse SA calculation unit 477,channel N−1 input port interface 413 or channel N+1 input port interface415, channel to channel arbitration unit 483 monitors during the PPD ARBtimeout the sources from which a PPD signal was not received for thereceipt of a PPD signal from these other sources. For example, if a PPDsignal initially is received from channel N1 input port interface 413,channel to channel arbitration unit 483 monitors the inputs from pulseSA calculation unit 477 and channel N+1 input port interface 415 duringthe PPD ARB timeout for the receipt of a PPD signal from either or bothof these other sources.

[0082] During the SA ARB timeout, channel to channel arbitration unit483 monitors the initial source of the PPD signal and each source fromwhich a PPD signal was received during the PPD ARB timeout for thereceipt of PDSA and PDSA valid signals. A non-initial source from whichno PPD signal is received during the PPD ARB timeout is no longerconsidered part of the arbitration process and, therefore, is notmonitored for such a signal during the SA ARB timeout. If a monitoredsource does not transmit a PDSA valid signal during the SA ARB timeout,the PDSA for the source is considered to be zero. Upon receipt of a PDSAvalid signal during the SA ARB timeout from a source, channel to channelarbitration unit 483 latches the PDSA signal from the source.

[0083] In accordance with the arbitration algorithm of channel tochannel arbitration unit 483, if the initial PPD signal transmitted tochannel to channel arbitration unit 483 in response to a detected signalis not from pulse SA calculation unit 477, and pulse SA calculation unit477 does not transmit a PPD signal during the PPD ARB timeout, channel Nloses the arbitration. On the other hand, if the initial PPD signaltransmitted to channel to channel arbitration unit 483 is not fromchannel N−1 input port interface 413 or channel N+1 input port interface415 and neither of these interfaces transmits a PPD signal to channel tochannel arbitration unit 483 during the PPD ARB timeout, channel N winsthe arbitration. If neither of these conditions occurs, then the winnerof the arbitration is the channel which transmitted to channel tochannel arbitration unit 483 the highest PDSA. For example, if the PDSAsignal from pulse SA calculation unit 477 has the highest magnitude,channel N wins the arbitration. On the other hand, if the PDSA signalfrom either channel N−1 or channel N+1 is greater than the magnitude ofthe PDSA signal from channel N, channel N loses the arbitration. In theevent that the PDSA signals from two channels are equal, the winner ofthe arbitration is the channel monitoring the lowest frequency band(e.g., N−1 or N).

[0084] If channel N loses the arbitration, channel to channelarbitration unit 483 transmits an arbitration lost signal (ARB LOST) topulse SA calculation unit 477 and bandwidth and frequency estimationunit 491. Upon receipt of this signal, these units terminate furthercalculations and return to a standby condition. On the other hand, ifchannel N wins the arbitration, channel to channel arbitration unit 483transmits an arbitration won signal (ARB WON) to output port interfacingunit 417.

[0085] Like channel to channel arbitration unit 483, bandwidth andfrequency estimation unit 491 remains in a standby condition until a PPDsignal from either pulse SA calculation unit 477, channel N−1 input portinterface 413 or channel N+1 input port interface 415 is received. Uponreceipt of a PPD signal from any of these sources, bandwidth andfrequency estimation unit 491 initiates two timeout periods as part ofthe process to estimate the detected signal's bandwidth and frequencyfor the analyzing receiver. Bandwidth and frequency estimation unit 491utilizes two programmable coefficients to execute this process withinthe predetermined timeout periods (PPD EST TIMEOUT and SA EST TIMEOUT),namely, frequency estimate inner bias (FREQ EST INNER BIAS) andbandwidth estimate inner threshold (BW EST INNER THOLD). As with theother programmable predetermined values, these timeouts and coefficientsalso are stored in registers and are transmitted from, e.g., usercontrol terminal 247.

[0086] First, within the period set by the PPD EST TIMEOUT, thebandwidth and frequency estimation unit 491 must receive PPD signalsfrom pulse SA calculation unit 477, channel N−1 input port interface 413and channel N+1 input port interface 415. Next, within the period set bythe SA EST TIMEOUT, the bandwidth and frequency estimation unit 491 mustreceive ESTSA data from channels N, N−1 and N+1. If these conditions arenot satisfied, the bandwidth and frequency estimation process isterminated immediately, and an error code is output in place of thefrequency estimate code. The frequency and bandwidth estimations utilizethe ESTSA data from channels N, N−1 and N+1, designated in the formulasbelow as, respectively, ESTSAN, ESTSAN−1 and ESTSAN+1, to calculate twovariables, namely, LACD and RACD. These formulas are:

LACD=(ESTSAN)−(ESTSAN−1)   (1)

RACD=(ESTSAN)−(ESTSAN+1)   (2)

[0087] LACD and RACD are used to calculate a frequency metric F inaccordance with the following formula:

F=LACD/(LACD+RACD)   (3)

[0088] The frequency estimation (FREQ) is a two bit value based upon acomparison of F to FREQ EST INNER BIAS. If F is less than FREQ EST INNERBIAS, the frequency is estimated to be biased toward the lower frequencyband. The two bit value for this condition is 00. On the other hand, ifF is equal to or greater than FREQ EST INNER BIAS, the frequency isestimated to be biased toward the upper frequency band. The two bitvalue for this condition is 11.

[0089] To estimate bandwidth, a bandwidth metric B, also based upon LACDand RACD, is calculated in accordance with the following formula:

B=LACD+RACD   (4)

[0090] BW EST INNER TROLD is a 16-word by 9-bit lookup table whichbandwidth and frequency estimation unit 491 indexes using the frequencymetric F to obtain BW EST INNER THOLD. The bandwidth estimate (BW) is asingle bit which is based upon a comparison of the bandwidth metric B tothe value of BW EST INNER THOLD obtained from the lookup table. If B isless than BW EST INNER THOLD, then the bandwidth of the detected pulseis estimated to be wide. Under this condition, BW is set to a 1. On theother hand, if B is greater than or equal to BW EST INNER THOLD, thenthe bandwidth of the detected pulse is estimated to be narrow. Underthis condition, BW is set to a 0.

[0091] When the calculations of the bandwidth and frequency estimationsare complete and the BW and FREQ signals are set to their correctvalues, bandwidth and frequency estimation unit 491 transmits anestimation ready signal (EST READY) to output port interfacing 417.Bandwidth and frequency estimation unit 491 transmits the BW and FREQsignals to channel N output port interface 487 of output portinterfacing 417.

[0092] Channel N−1 output port interface 485 and channel N+1 output portinterface 489 transmit the PPD, PDSA and ESTSA signals from channel N tochannels N−1 and N+1, respectively. A signal (not shown) from each ofthese interfaces is asserted when these signals are valid. The timeperiod that these output signals are asserted (ADJ width) also is aprogrammable coefficient.

[0093] Channel N output port interface 487 transmits a plurality ofsignals to the resource allocation system. These signals include: thecontinuous wave detection signal from pulse data capture unit 5 (CDsignal); the PPD signal from pulse SA calculation unit 477 (PD signal);the PDSA signal from pulse SA calculation unit 477 or the CWSA signalfrom CW SA calculation unit 481 (SA signal); a signal indicating thatthe SA signal is valid and corresponds to the PDSA signal (CPA signal);the BW signal from bandwidth and frequency estimation unit 491 (BWsignal); the FREQ signal from bandwidth and frequency estimation unit491 (FREQ signal); a signal indicating that the SA signal is valid andcorresponds to the CWSA signal (CCA signal); and the ADF signal frompulse SA calculation unit 477 identifying the target pulse data captureunit (ADF signal). If channel N does not win an arbitration conducted bychannel N, only the CD signal, CWSA signal and the CCA signal can betransmitted to the resource allocation system. The remaining signals,namely, the PPD signal, the PDSA signal, the CPA signal, the BW signal,the FREQ signal and the ADF signal all correspond to the detection of apulse. These signals, therefore, are transmitted to the resourceallocation system only if channel N wins the arbitration

[0094] Upon receipt of an ARB WON signal, channel N output portinterface 487 immediately transmits the PD signal to the resourceallocation system. Channel N output port interface 487 continues thistransmission for the duration of the PPD input signal from pulse SAcalculation unit 477. Channel N output port interface 487 latches thePDSA and ADF signals, and the BW and FREQ signals, respectively, uponreceipt of the PDSA VALID signal from pulse SA calculation unit 477 andthe EST READY signal from bandwidth and frequency estimation unit 491.Upon the occurrence of these latchings, the CPA signal is asserted toindicate that these data are ready and valid. The width of the CPA pulsealso is a programmable coefficient of from between 1 and 16 clock cycles(CPA width coefficient).

[0095] Channel N output port interface 487 immediately transmits the CDsignal upon receipt from pulse data capture unit 5. Upon receipt of theCWSA VALID signal from CW SA calculation unit 481, the CWSA value fromthis unit is latched onto the SA output of channel N output portinterface 487 and a pulse is asserted on the CCA output to indicate thatthese data are ready and valid for a continuous wave detection. Asindicated above, these transmissions occur regardless of the outcome ofthe arbitration for a pulse detection.

[0096] Each transfer of pulse or continuous wave data from channel Noutput port interface 487 occurs upon completion of the previoustransfer of such data. If the PD and CD signals are ready and valid,however, these signals are transferred to the resource allocation systemimmediately without waiting for such completion.

[0097] Output port interfacing 417 transmits a signal to pulse SAcalculation unit 477 upon completion of a transfer of pulse data to theresource allocation system to indicate that the interfacing is availablefor receipt of additional pulse data (CPA OUT CMPLET signal). In asimilar manner, output port interfacing 417 transmits a signal to CW SAcalculation unit 481 upon completion of a transfer of CW data to theresource allocation system to indicate that the interfacing is availablefor the receipt of additional CW data (CCA OUT CMPLET signal).

[0098] The channel processor preferably is fabricated using fieldprogrammable gate arrays or application specific integrated circuits onone or more chips and circuit boards. In the alternative, the logic andfunctions described above for the channel processor may be implementedusing any circuitry capable of executing these functions and logic,e.g., a programmed microprocessor, special purpose computer, discretehard-wired logic gates, etc.

[0099] Although the invention herein has been described with referenceto particular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A channelizing receiver, said channelizing receiver including aplurality of channel receivers, each said channel receiver comprising: aplurality of filters, each of said filters receiving an input signalrepresenting electromagnetic signals falling within a frequency rangebeing monitored by said channel receiver and transmitting an outputsignal representing electromagnetic signals falling within a segment ofsaid frequency range; a plurality of threshold detectors, each of saidthreshold detectors receiving one of said output signals and producing adetection signal if said one output signal exceeds a predeterminedthreshold; a signal amplitude calculation unit for receiving said outputsignals and said detection signals, starting an initial timing period inresponse to the receipt of one of said detection signals indicatingdetection of an electromagnetic signal and producing a magnitude signalproviding the magnitude during said initial timing period of the outputsignal to which said one detection signal corresponds; and a channel tochannel arbitration unit for receiving said magnitude signal and a firstother magnitude signal from a first other channel receiver of saidchannelizing receiver produced in response to said first other channelreceiver's detection of said electromagnetic signal during said initialtiming period within a first other frequency range being monitored bysaid first other channel receiver, comparing said magnitude signal andsaid first other magnitude signal, and if said first other magnitudesignal is greater than said magnitude signal, inhibiting thetransmission from said channel receiver of data responsive to said onedetection signal.
 2. A channelizing receiver as in claim 1, wherein saidmagnitude signal provides the peak amplitude reached during said initialtiming period by said output signal.
 3. A channelizing receiver as inclaim 1, wherein said plurality of filters comprises a plurality of lowpass filters having different cut off frequencies.
 4. A channelizingreceiver as in claim 3, wherein said signal amplitude calculation unitis adapted for initiating an additional timing period in response tosaid one detection signal, identifying a group of said thresholddetectors producing detection signals during said additional timingperiod and producing a peak amplitude signal providing the peakamplitude reached during said additional timing period by the outputsignal corresponding to the detection signal produced by the thresholddetector of said group associated with the low pass filter having thelowest cut off frequency.
 5. A channelizing receiver as in claim 1,wherein said channel to channel arbitration unit is adapted forpermitting the transmission from said channel receiver of said data ifsaid first other magnitude signal is less than said magnitude signal. 6.A channelizing receiver as in claim 5, wherein said data provides thebeginning of a pulse of said electromagnetic signal, the end of saidpulse and an estimate of the frequency and bandwidth of said pulse.
 7. Achannelizing receiver as in claim 1, wherein said channel to channelarbitration unit is adapted for receiving a second other magnitudesignal from a second other channel receiver of said channelizingreceiver produced in response to said second other channel receiver'sdetection of said electromagnetic signal during said initial timingperiod within a second other frequency range being monitored by saidsecond other channel receiver, comparing said magnitude signal with saidsecond other magnitude signal, and if one or both of said first othermagnitude signal and said second other magnitude signal is greater thansaid magnitude signal, inhibiting the transmission from said channelreceiver of said data.
 8. A channelizing receiver as in claim 7, whereinsaid first other frequency range is immediately below said frequencyrange and said second other frequency range is immediately above saidfrequency range.
 9. A channelizing receiver as in claim 7, wherein saidchannel to channel arbitration unit is adapted for permitting thetransmission from said channel receiver of said data if both said firstother magnitude signal and said second other magnitude signal are lessthan said magnitude signal.
 10. A channelizing receiver as in claim 9,wherein said data provide the beginning of a pulse of saidelectromagnetic signal, the end of said pulse and an estimate of thefrequency and bandwidth of said pulse.
 11. A channelizing receiver as inclaim 4, wherein each said channel receiver further comprises abandwidth and frequency estimation unit for receiving said peakamplitude signal and a first other peak amplitude signal from said firstother channel receiver produced in response to said first other channelreceiver's detection of said electromagnetic signal during saidadditional timing period, and producing an estimation signal providingan estimate of the frequency and bandwidth of said electromagneticsignal based upon said peak amplitude signal and said first other peakamplitude signal.
 12. A channelizing receiver as in claim 11, whereinsaid bandwidth and frequency estimation unit is adapted for receiving asecond other peak amplitude signal from a second other channel receiverof said channelizing receiver produced in response to said second otherchannel receiver's detection of said electromagnetic signal during saidadditional timing period within a second other frequency range beingmonitored by said second other channel receiver, and producing saidestimation signal based upon said peak amplitude signal, said firstother peak amplitude signal and said second other peak amplitude signal.13. A channelizing receiver as in claim 12, wherein said first otherfrequency range is immediately below said frequency range and saidsecond other frequency range is immediately above said frequency range.14. A channelizing receiver as in claim 2, wherein said signal amplitudecalculation unit is adapted for identifying said peak amplitude byidentifying a predetermined number of consecutive samples of said oneoutput signal having values less than said peak amplitude.
 15. Achannelizing receiver as in claim 1, wherein each said channel receiverfurther comprises a multiplexer for receiving said output signals andselecting particular ones of said output signals for transmission tosaid threshold detectors.
 16. A channelizing receiver as in claim 1,wherein said filters are finite impulse response filters.
 17. Achannelizing receiver as in claim 1, wherein each said channel receiverfurther comprises a bandpass filter for receiving from an antennaelectromagnetic signals being monitored by said channelizing receiverand transmitting to said channel receiver said electromagnetic signalsfalling within said frequency range being monitored by said channelreceiver.
 18. A channelizing receiver as in claim 17, wherein each saidchannel receiver further comprises a log detector for receiving fromsaid bandpass filter said electromagnetic signals being monitored bysaid channel receiver and providing an output signal proportional to thepower of said electromagnetic signals being monitored by said channelreceiver.
 19. A channelizing receiver as in claim 18, wherein each saidchannel receiver further comprises an analog to digital converter forreceiving said output signal from said log detector and providing adigital representation of said output signal for transmission to saidplurality of filters.
 20. A channelizing receiver as in claim 17,wherein said antenna is an orthogonally polarizing antenna fororthogonally polarizing said electromagnetic signals being monitored bysaid channelizing receiver.
 21. A channelizing receiver as in claim 1,wherein said electromagnetic signals are radio frequency signals.
 22. Achannelizing receiver, said channelizing receiver including a pluralityof channel receivers, each said channel receiver comprising: a thresholddetector for receiving an input signal representative of anelectromagnetic signal detected by said channel receiver and producing adetection signal if said input signal exceeds a predetermined threshold;an output interface for transmitting data responsive to said detectionsignal from said channel receiver; a signal amplitude calculation unitfor producing a magnitude signal providing the magnitude of said inputsignal; and a channel to channel arbitration unit for comparing saidmagnitude signal to a first other magnitude signal from a first otherchannel receiver of said channelizing receiver produced in response tosaid first other channel receiver's detection of said electromagneticsignal, and if said magnitude signal is less than said first othermagnitude signal, inhibiting said output interface from transmittingsaid data.
 23. A channelizing receiver as in claim 22, wherein saidchannel to the channel arbitration unit is adapted for comparing saidmagnitude signal to a second other magnitude signal from a second otherchannel receiver of said channelizing receiver produced in response tosaid second other channel receiver's detection of said electromagneticsignal, and inhibiting said output interface from transmitting said dataif said magnitude signal is less than one or both of said first othermagnitude signal and said second other magnitude signal.
 24. Achannelizing receiver as in claim 23, wherein each said channel receiverfurther comprises a bandwidth and frequency estimation unit and whereinsaid data comprises an estimate of the bandwidth and frequency of saidelectromagnetic signal calculated by said bandwidth and frequencyestimation unit on the basis of an additional magnitude signal producedby said signal amplitude calculation unit in response to said detectionsignal, a first other additional magnitude signal from said first otherchannel receiver produced in response to said first other channelreceiver's detection of said electromagnetic signal and a second otheradditional magnitude signal from said second other channel receiverproduced in response to said second other channel receiver's detectionof said electromagnetic signal.
 25. A channelizing receiver as in claim22, wherein said channel to channel arbitration unit is adapted forpermitting the transmission from said output interface of said data ifsaid magnitude signal is greater than said first other magnitude signal.26. A channelizing receiver as in claim 23, wherein said channel tochannel arbitration unit is adapted for permitting the transmission fromsaid output interface of said data if said magnitude signal is greaterthan both said first other magnitude signal and said second othermagnitude signal.
 27. A channelizing receiver as in claim 24, whereinsaid data provides the beginning of a pulse of said electromagneticsignal, the end of said pulse and an estimate of the frequency andbandwidth of said pulse calculated by said bandwidth and frequencyestimation unit.
 28. A channelizing receiver as in claim 23, whereinsaid channel receiver is adapted for monitoring a segment of a frequencybandwidth monitored by said channelizing receiver, said first otherchannel receiver is adapted for monitoring a first other segment of saidfrequency bandwidth and said second other channel receiver is adaptedfor monitoring a second other segment of said frequency bandwidth.
 29. Achannelizing receiver as in claim 28, wherein said segment is contiguousto said first other segment and said second other segment.
 30. Achannelizing receiver as in claim 22, wherein said signal amplitudecalculation unit is adapted for identifying said magnitude of said inputsignal by identifying a predetermined number of consecutive samples ofsaid input signal having values less than said magnitude.
 31. Achannelizing receiver as in claim 22, wherein said electromagneticsignal is a radio frequency signal.
 32. A channelizing receiver as inclaim 22, wherein each said channel receiver further comprises one ormore further threshold detectors, each of said one or more furtherthreshold detectors receiving a respective one of one or more furtherinput signals representative of said electromagnetic signal detected bysaid channel receiver and producing a detection signal if saidrespective further input signal exceeds a predetermined threshold.
 33. Achannelizing receiver, said channelizing receiver including a pluralityof channel receivers, each said channel receiver comprising: a firstchannel for receiving a first component of an electromagnetic signal,said first channel including a first bandpass filter for transmittingsaid first component if said first component has a frequency fallingwithin the bandpass of said first bandpass filter, a first log detectorfor receiving said first component and providing a first video signalrepresentative of said first component, a first analog to digitalconverter for receiving said first video signal and providing a firstdigital signal representative of said first video signal; a secondchannel for receiving a second component of said electromagnetic signal,said second channel including a second bandpass filter for transmittingsaid second component if said second component has a frequency fallingwithin the bandpass of said second bandpass filter, a second logdetector for receiving said second component and providing a secondvideo signal representative of said second component, a second analog todigital converter for receiving said second video signal and providing asecond digital signal representative of said second video signal; abaseband combiner for combining said first digital signal and saidsecond digital signal to provide a combined digital signal; and achannel processor for receiving said combined digital signal andtransmitting data responsive to the detection of said electromagneticsignal if the magnitude of said combined digital signal exceeds apredetermined threshold.
 34. A channelizing receiver as in claim 33,wherein said channel processor is adapted for prohibiting thetransmission of said data if the magnitude of said combined digitalsignal is less than the magnitude of a first other combined digitalsignal produced by a first other channel receiver of said plurality ofchannel receivers in response to said first other channel receiver'sdetection of said electromagnetic signal.
 35. A channelizing receiver asin claim 33, wherein said data includes an estimate of the frequency andbandwidth of said electromagnetic signal calculated by said channelprocessor.
 36. A channelizing receiver as in claim 34, wherein said dataincludes an estimate of the frequency and bandwidth of saidelectromagnetic signal calculated by said channel processor.
 37. Achannelizing receiver as in claim 33, wherein said baseband combiner isadapted for disabling said combining and transmitting to said channelprocessor only one of said first digital signal or said second digitalsignal.
 38. A channelizing receiver as in claim 33, wherein said channelprocessor comprises a plurality of low pass filters having different cutoff frequencies for receiving said combined digital signal andseparating said combined digital signal into a plurality of separatesignals falling within different frequency ranges.
 39. A channelizingreceiver as in claim 38, wherein said channel processor furthercomprises a multiplexer and a plurality of threshold detectors, saidmultiplexer being adapted for receiving said plurality of separatesignals and selecting particular ones of said separate signals fortransmission to particular ones of said threshold detectors, each ofsaid threshold detectors producing a threshold signal if the separatesignal received by said threshold detector exceeds a selected threshold.40. A channelizing receiver as in claim 39, wherein said channelprocessor further comprises a signal amplitude calculation unit forreceiving said threshold signals and said separate signals and producingduring a selected period initiated by one of said threshold signals apeak amplitude signal providing the peak amplitude reached during saidselected period of the separate signal to which said one thresholdsignal corresponds.
 41. A channelizing receiver as in claim 40, whereineach said channel receiver further comprises a channel to channelarbitration unit for receiving said peak amplitude signal and a firstother peak amplitude signal from a first other channel receiver of saidchannelizing receiver produced in response to said first other channelreceiver's detection of said electromagnetic signal during said selectedperiod, comparing said peak amplitude signal and said first other peakamplitude signal, and if said first other peak amplitude signal isgreater than said peak amplitude signal, inhibiting said transmitting ofsaid data responsive to the detection of said electromagnetic signal.42. A channelizing receiver as in claim 38, wherein said plurality oflow pass filters are adapted for detecting wideband electromagneticsignals and said channel processor further comprises a second pluralityof low pass filters having different cut off frequencies for receivingsaid combined digital signal and separating said combined digital signalinto a second plurality of separate signals falling within differentfrequency ranges, said second plurality of low pass filters beingadapted for detecting narrowband electromagnetic signals.
 43. Achannelizing receiver as in claim 42, wherein said channel processorfurther comprises a multiplexer and a plurality of threshold detectors,said multiplexer being adapted for receiving said second plurality ofseparate signals and selecting one of said second plurality of separatesignals for transmission to a threshold detector, said thresholddetector producing a threshold signal if said one separate signalexceeds a selected threshold.
 44. A channelizing receiver as in claim43, wherein said channel processor further comprises a signal amplitudecalculation unit for receiving said threshold signal and said oneseparate signal and producing during a selected period initiated by saidthreshold signal a peak amplitude signal providing the peak amplitudereached during said selected period of said separate signal.
 45. Achannelizing receiver as in claim 44, wherein each said channel receiverfurther comprises an output interface for receiving said peak amplitudesignal and transmitting said peak amplitude signal to a resourceallocation system.
 46. A channelizing receiver as in claim 33, whereinsaid electromagnetic signal is a radio frequency signal.
 47. Achannelizing receiver as in claim 33, wherein said first component andsaid second component are received from one or more polarizing antennas,and said first component is a first polarized component of saidelectromagnetic signal and said second component is a second polarizedcomponent of said electromagnetic signal.
 48. A channelizing receiver asin claim 47, wherein said one or more polarizing antennas areorthogonally polarizing antennas, and said first polarized component andsaid second polarized component are orthogonally polarized.
 49. A methodfor detecting an electromagnetic signal falling within a frequency band,said method comprising: providing a channelizing receiver having aplurality of channels, each of said channels including a bandpass filterfor transmitting signals within a segment of said frequency band;providing for each channel a channel processor for receiving saidsignals, producing a detection signal indicating the detection of saidelectromagnetic signal and producing a magnitude signal indicating themagnitude of said electromagnetic signal; identifying within apredetermined time period a group of said channel processors producingsaid detection signals; comparing for said group the magnitude signalscorresponding to said detection signals to identify the magnitude signalindicating the highest magnitude; and transmitting for said group fromsaid channelizing receiver data corresponding to one of said detectionsignals only if said one detection signal is associated with saidmagnitude signal indicating said highest magnitude.
 50. A method as inclaim 49, further comprising assessing the relative magnitudes of saidmagnitude signals of said group and wherein said data comprisesinformation providing an estimate of the frequency and bandwidth of saidelectromagnetic signal based upon said relative magnitudes.
 51. A methodas in claim 49, wherein said magnitude signal indicates the peakamplitude of said electromagnetic signal reached during saidpredetermined time period.
 52. A method as in claim 50, wherein saiddata comprises information identifying the beginning of a pulse of saidelectromagnetic signal and the end of said pulse.
 53. A method as inclaim 49, wherein each said segment of said frequency band is contiguousto at least one other segment of said frequency band.
 54. A method as inclaim 49, wherein said electromagnetic signal is a radio frequencysignal.
 55. A channelizing receiver, said channelizing receiverincluding a plurality of channel receivers, each said channel receivercomprising: receiving means for receiving an input signal representativeof an electromagnetic signal detected by said channel receiver andproducing a detection signal if said input signal exceeds apredetermined threshold; transmitting means for transmitting dataresponsive to said detection signal from said channel receiver;producing means for producing a magnitude signal providing the magnitudeof said input signal; and comparing means for comparing said magnitudesignal to a first other magnitude signal from a first other channelreceiver of said channelizing receiver produced in response to saidfirst other channel receiver's detection of said electromagnetic signal,and if said magnitude signal is less than said first other magnitudesignal, inhibiting said transmitting means from transmitting said data.56. A channelizing receiver as in claim 55, wherein said comparing meanscomprises means for comparing said magnitude signal to a second othermagnitude signal from a second other channel receiver of saidchannelizing receiver produced in response to said second other channelreceiver's detection of said electromagnetic signal, and inhibiting saidtransmitting means from transmitting said data if said magnitude signalis less than one or both of said first other magnitude signal and saidsecond other magnitude signal.
 57. A channelizing receiver as in claim56, wherein each said channel receiver further comprises estimatingmeans for estimating the bandwidth and frequency of said electromagneticsignal on the basis of an additional magnitude signal produced by saidproducing means in response to said detection signal, a first otheradditional magnitude signal from said first other channel receiverproduced in response to said first other channel receiver's detection ofsaid electromagnetic signal and a second other additional magnitudesignal from said second other channel receiver.
 58. A channelizingreceiver as in claim 55, wherein said comparing means includes means forpermitting the transmission from said transmitting means of said data ifsaid magnitude signal is greater than said first other magnitude signal.59. A channelizing receiver as in claim 56, wherein said comparing meansincludes means for permitting the transmission from said outputinterface of said data if said magnitude signal is greater than bothsaid first other magnitude signal and said second other magnitudesignal.
 60. A channelizing receiver as in claim 57, wherein said datafurther provides the beginning of a pulse of said electromagneticsignal, the end of said pulse and an estimate of the frequency andbandwidth of said pulse calculated by said estimating means.
 61. Achannelizing receiver as in claim 56, wherein said channel receiverfurther comprises means for monitoring a segment of a frequencybandwidth monitored by said channelizing receiver, said first otherchannel receiver comprises means for monitoring a first other segment ofsaid frequency bandwidth and said second other channel receivercomprises means for monitoring a second other segment of said frequencybandwidth.
 62. A channelizing receiver as in claim 61, wherein saidsegment is contiguous to said first other segment and said second othersegment.
 63. A channelizing receiver as in claim 55, wherein saidproducing means comprises means for identifying said magnitude of saidinput signal by identifying a predetermined number of consecutivesamples of said input signal having values less than said magnitude. 64.A channelizing receiver as in claim 55, wherein said electromagneticsignal is a radio frequency signal.